1968 and up Shelby parts carried Ford #'s and went through the Ford system (example: S8MS-13449-A was a taillight door, Ford simply used the letter "S" to begin the Shelby-specific numbers. I don't know if they'll do that with the new cars, considering that the part numbering system as gotten alot more complex/confusing today...)
Absolutely. You may have trouble tracking down some of the part numbers early on though. I just ordered a bunch of GT500 intercooler system parts for my GT yesterday. My Ford guy used an inbound GT500 VIN to gain access to some of the hard-to-find part numbers.
Using a VIN number sounds like a good trick. I'll see what the parts folks at my Friendly Ford dealer can do. I'm looking for the front lower spoiler. What they have on the GT 500 looks very good. I'm just not sure if it will fit my '05 GT fascia. But, it's worth a look.
that would be a nice addition. make sure you find a really competent shop to drill the holes, or find a used trunk that already has the holes. i have seen many shop add a spoiler, but under the spoiler are several large holes, because they could not mark/drill the holes properly.